The Sun Block or Sun Screen is the Lotion that absorbs or reflects some of the sun's ultraviolet (UV) radiation on the skin exposed to sunlight and thus helps protect against sunburn. Everyday exposure to sunlight cause UV rays adverse effects on skin leads to irritation,sun burn, tanning, scars and also skin cancer. One way to protect your skin is the use of sunscreen.
We use sunscreen to block ultraviolet light from damaging the skin.
1.UVA
There are two different concepts of protection:
We use sunscreen to block ultraviolet light from damaging the skin.
There are two categories of UV light
1.UVA
2.UVB
UVA (ultraviolet-A):
Long- wave solar rays of 320-400 nanometers (billionths of a meter). Although less likely than UVB to cause sunburn, UVA penetrates the skin more deeply, and is considered the chief culprit behind wrinkling, leathering, and other aspects of "photoaging." The latest studies show that UVA not only increases UVB 's cancer-causing effects, but may directly cause some skin cancers, including melanomas.
UVB (ultraviolet-B):
Short-wave solar rays of 290-320 nanometers. More potent than UVA in producing sunburn, these rays are considered the main cause of basal and squamous cell carcinomas as well as a significant cause of melanoma. UVB causes sunburn, SPF, numbers were introduced in 1962 to measure a sunscreen's effect against UVB rays.
Short-wave solar rays of 290-320 nanometers. More potent than UVA in producing sunburn, these rays are considered the main cause of basal and squamous cell carcinomas as well as a significant cause of melanoma. UVB causes sunburn, SPF, numbers were introduced in 1962 to measure a sunscreen's effect against UVB rays.
Sunblocks and sunscreens:
Sunscreens chemically absorb UV rays, sunblocks physically deflect them. Sunscreen has long blocked UVB effectively, but until recently provided less UVA protection. New ingredients such as octylcrylene and the benzophenones have improved sunscreen's defenses against shorter UVA rays, and the revolutionary chemical avobenzone (Parsol 1789) works against all UVA wavelengths.
Sunblocks have also markedly improved. New preparations such as micronized titanium dioxide are less conspicuous on the skin and offer substantial protection against both UVA and UVB.
SPF (sun protection factor):
SPF measures the length of time a product protects against skin reddening from UVB, compared to how long the skin takes to redden without protection. If it takes 20 minutes without protection to begin reddening, using an SPF 15 sunscreen theoretically prevents reddening 15 times longer -- about 5 hours. (Actually, it may take up to 24 hours after sun exposure for redness to become visible.) To maintain the SPF, reapply sunscreen every two hours and right after swimming.
The Skin Cancer Foundation recommends SPF's of at least 15, which block 93 percent of UVB. While SPF's higher than 30 block only 4 percent more UVB, they may be advisable for sun-sensitive individuals, skin cancer patients, and people at high risk of developing skin cancer. They also allow some margin for error if too little sunscreen is applied.
While SPF is the universal measurement of UVB protection, no comparable standard exists for UVA. Scientists worldwide are working to develop a standardized testing and certification method to measure UVA protection.
SPF numbers start at 2 and have just recently reached 70. To figure out how long you can stay in the sun with a given SPF, use this equation:
Minutes to burn without sunscreen x SPF number
= maximum sun exposure time
= maximum sun exposure time
There are two different concepts of protection:
1.Chemical sunscreens
2.Physical sunblocks
Chemical Sunscreens
A chemical sunscreen works by absorbing, reflecting or scattering the sun’s rays (UV radiation) before they affect the skin. The active ingredient in sunscreens that protects you against the sun
- Octylcrylene
- Avobenzone
- Octinoxate
- Octisalate
- Oxybenzone
- Homosalate
- 4-MBC
- Mexoryl SX and XL
- Tinosorb S and M
- Uvinul T 150
- Uvinul A Plus
UVA-Filter
butyl methoxydibenzolmethane (dibenzolmethane)
Is often used to filter UVA but which is known to be very unstable.
UVB-Filter
- thylbenzylidene camphor
Is used to filter UVB and in addition functions as a stabilizer for UV filter- yl triazone/ octocrylene
Its also used as a UVB filter and has the ability to stabilize the UVA filter.- yl methoxycinnamate
Physical Sunblocks
A physical sunscreen sits on the skin's surface and reflects or scatters UV radiation before it is able to damage the skin. These two forms of protection have different methods of achieving a similar goal. Physical sunscreens containing zinc oxide or titanium dioxide protect against UVB and UVA. However, zinc oxide blocks more UV radiation than titanium dioxide and, therefore, is the preferred ingredient.
Broad Spectrum Sunscreen
A sunscreen that screens both UVA and UVB rays. UVA rays are longer in wavelength and penetrate more deeply than UVB rays. It Protects you both from UVA and UVB rays and adverse affects caused by them on skins. So its advisable to buy a sunscreen with board spectrum of SPF least 15.
Tips To Apply Sunscreen Lotion
- Apply all over the body parts exposed to the sun light.
- Make sure that you apply sunscreen lotion at least 30 minutes before you go out, as it would allow skin to absorb the lotion
- Reapply sunscreen every 2 hours when outdoors
- The major part exposed to the sunlight is the skin, which also first attracts other by the beauty. So to make you beautiful keep your skin young, attractive, spotless and mainly protect it from sun rays, inspite whatever your complexion might be. Indeed you look gorgeous!
For Further Details:-
No comments:
Post a Comment